The SOX family of transcription factors belongs to the High Mobility Group (HMG) box superfamily of DMA-binding proteins and regulates many developmental processes, such as cell specification and organ development. The SOX family, comprised of subgroups A-J, is characterized by a highly conserved HMG domain, the DNA binding domain. Two members of SOX family subgroup E, Sox9 and Sox10, are further distinguished by the presence of two uncharacterized homology domains, termed E1 and E2. Both Sox9 and Sox10 have been implicated in inner ear development, and specific mutations in these genes can cause congenital deafness. The aim of this application is to investigate the functional and mechanistic role that these two SOX family members play in the development of the otic placode. This will be explored by looking at potential functional redundancy between Sox9 and Sox10, different protein-protein interactions, and possible post-translational modifications.